Method for triggering a security tag

Abstract

A method of triggering a security tag attached to an article for deterring theft of said article comprises: emitting a first trigger signal in a first defined area; emitting a second trigger signal in a second defined area, the second trigger signal being different from the first trigger signal; providing a security tag including an activation sensor configured to detect the first and second trigger signals and control circuitry configured to trigger a theft deterrent module of the security tag upon detection of a trigger signal sequence comprising detection of the second trigger signal within a predefined time period after detection of the first trigger signal.

1 . A method of triggering a security tag attached to an article for deterring theft of said article, the method comprising:
 emitting a first trigger signal in a first defined area;   emitting a second trigger signal in a second defined area, the second trigger signal being different from the first trigger signal;   providing a security tag including an activation sensor configured to detect the first and second trigger signals and control circuitry configured to trigger a theft deterrent module of the security tag upon detection of a trigger signal sequence comprising detection of the second trigger signal within a predefined time period after detection of the first trigger signal.   
     
     
         2 . The method of  claim 1 , wherein the trigger signal sequence further comprises detecting loss of both the first and second trigger signals after detection of the second trigger signal. 
     
     
         3 . The method of  claim 1 , wherein the control circuitry is configured to trigger the theft deterrent module after a predefined period of time has elapsed after detection of the second trigger signal. 
     
     
         4 . The method of  claim 1 , wherein the control circuitry is configured not to trigger the theft deterrent module if the activation sensor detects the first trigger signal within a predefined time period after detection of the second trigger signal. 
     
     
         5 . The method of  claim 1 , wherein the frequency of the first trigger signal is different to the frequency of the second trigger signal. 
     
     
         6 . The method of  claim 1 , wherein the first and second trigger signals are at the same frequency but include a different identifier. 
     
     
         7 . The method of  claim 1 , wherein at least a part of the first and second defined areas are on opposite sides of an exit of a retail store. 
     
     
         8 . The method of  claim 1 , wherein the first defined area overlaps the second defined area. 
     
     
         9 . The method of  claim 1 , wherein the theft deterrent module comprises an alarm module. 
     
     
         10 . The method of  claim 1 , wherein the theft deterrent module comprises a benefit denial module. 
     
     
         11 . The method of  claim 10 , wherein the security tag further comprises an alarm module, and the control circuitry is configured to trigger the alarm module immediately after detection of the first or second trigger signals by the activation sensor. 
     
     
         12 . The method of  claim 1 , wherein each of the first and second trigger signals is one of an RF signal, an acousto-magnetic signal or an electromagnetic signal.